Combined pressure gauge and valve



J. E. GRAHAM. COMBINED PRESSURE GAUGE AND VALVE. APPLICATION FILED NOV. :0. I920.

1 428,776 Patented Sept. 12, 1922.

Patented Sept. 12, 1922..

unrreo STATES PATENT OFFICE.

COMBINED ERESSURE GAUGE AND VALVE.

Application filed November 10, 1920. Serial No. 423,072.

To all whom it may concern:

Be it known that I, JOHN ELrHINs'roNn GRAHAM, a subject of the King of Great Britain and Ireland, residing at London, England, have invented certain new and useful Improvements in Combined Pressure Gauges and Valves, of which the following is a specification.

This invention relates to improvements in combined valve and pressure gauges for pneumatic tyres and the like and refers more particularly to devices of the kind in question wherein a piston or plunuger is employed, against one side of which the air acts to move the said plunger outwardly against the action of a spring.

One of the principal features of the invention consists in the employment of adjusting means whereby the device may be set or adjusted to indicate any predetermined pressure, said adjusting means being arranged in such a manner that the movement of the plunger to indicate when the required pressure has been reached is reduced to a minimum, whilst adjusting means gives any indication of pressure without increasing the normal length of the device.

A second feature of the invention consists in the employment of a valve which acts as a stop valve to cut off communication between the interior of the tyre or the like and the pressure gauge when the latter is not recording and to act as a check valve when the pressure gauge is recording.

A third feature of the invention is the construction of the device such that the plunger or piston and its stem may be held rigid when no record is being taken with the object of preventing harmful vibration.

In order that the invention may be readily understood, reference is made to the accompanying drawings in which Fig. 1 is a vertical sectional elevation through a combined valve and air pressure gauge constructed according to the invention, and showing the piston and valve on the lower seat with check valve closed.

Fig. 2 is a similar view of the lower portion of the device in which the piston and valve are off the lower seat and the check valve closed.

Fig. 3 is an elevation of the dust cap showingthe locking means for retaining same in position.

Fig. 4 is a side view of the top of the device showing recording cap in position.

Fig. 5 is a horizontal sectional View on the line 5-5 Fig. 1.

Fig. 6 is a partial view of the plunger to an enlarged scale and of slightly modified construction.

Referring to the drawings 0!. indicates the barrel or casing having a flange (1 and adapted to be secured in the usual manner to a pneumatic tyre. a is a passage or port for air. within the barrel is slidably mounted a piston 79 having connected thereto a tubular rod 0 the upper opposite end of which is externally threaded at c to receive the screwed flexible connection of a pump or the like. On the tubular rod is a slidably mounted ring or plate 6 forming a sliding fit within the barrel, as shown and provided with a series of projecting tongues or lugs 0 adapted to engage and be supported by longitudinal. grooves a in the interior of the barrel and with an internal projection c adapted to engage a longitudinal groove 0 in the outer periphery of the tubular rod 0. By this means the tubular rod 0 is secured against independent rotation within the barre a.

The interior of the barrel is threaded at its upper end to receive a screwed loading plug d provided with a central longitudinal recess (Z for the reception of a coil spring f and with a central hole at its upper end through which the tubular rod 0 slides. The lower end of the spring 7 engages with and is supported by the upper surface of the ring 0 which is normally supported by the lower end of the grooves a. The upper edge a of the barrel is preferably tapered oil, as shown,-and the outer surface of the loading plug d is provided with a series of graduations or markings as shown in Fig. 2, which markings may be arranged in any suitable manner to co-operate with the edge a of the barrel. It will thus be seen that the loading plug may be adjusted longitudinally within the barrel a by rotating the same to increase or decrease the load on the spring, the markings being arranged to in.

dicate pressure to be applied to the underside of the piston in order to raise the same together with the rod 0, to record.

The upper end of the barrel a is externally screwed to receive the recording cap 9 which is preferably provided with a shoulder or valve like seating g adapted to locate the cap when the same is screwed on to the barrel, the shoulder engaging the tapered upper edge a of the barrel as shown in Fig. 1. The upper end of the recording cap 1s externally threaded at g to receive asorewed dust cap it hereinafter referred to.

The tubular rod 0 connected to the piston is provided in the neighbourhood of its upper end with grooves or the like c fc respectively, the upper groove 0 being arranged to coincide with the upper edge 9 of the recording cap 9 when the desired pressure has been reached, whilst the groove (2 registers-therewith when the air pressure has exceeded within certain limits the predetermined pressure.

Mounted on or within the piston Z) is a valve of rubber or other suitable material, indicated at 2', to which is rigidly attached a rod 7i; extending upwardly through the tube a. This valve constitutes both a stop valve for cutting off communication througlr the port between the tyre and the plunger, when the pressure gauge is not in use, whilst when the tyre is being inflated or it is desired to ascertain whether the tyre is fully inflated, the valve is moved upwardly against the plunger by air pressure within the tyre to close the passage 0 through which the rod passes and thus constitutes a check valve, so that the whole of the pressure of air acts upon the under surface of the plunger 7).

In, order to cause the valve to close, the air passage a when the tyre is inflated to the desired extent, the dust cap it is provided atthe bottom of-the recess therein, with a small spring or other means m which engages the top of the tubular rod 0 and when the dust cap is screwed tightly .on to the portion 9 of the recording cap, this rod-is pressed downwardly until the valve i closes the aperture a In order to prevent disconnection of the valve from the plungerand tubular rod, the rod k of the valve carries in the neighbourhood of its upper, end a smallsplit metallic sleeve 12 the lower edges of which engage. a shoulder a formed on the interior of the tubular rod 0. The rod 7:; is preferably flattened or provided with projections 717 in order to retain the split sleeve in position.

In order to prevent the dust cap vit from becoming disengaged from the recording cap g, itslower end is partially cut through, as shownvat h so as to leave a partially severed annular ring or ,the like if, the lower surface of which is provided with one or more projecting tongues or the like it preferably arranged on the ring at a point furthest from the unsevered portion of the ring if. This projection cooperates with a series of radially disposed grooves 9* formed on a shoulder g of the recording cap. By this arrangement when the dust cap is screwed down tightly on to the threaded portion 9 of the recording cap the projection on the partly severed ring 71/2 engages one of the radial grooves g and the transverse cut 71 gives the ring if a slight springiness which is suflicient to maintain the project-ion g in engagement with the groove and thus prevent loosening of the cap due to vibration.

As will be seen more clearly in F 6 the plunger 5 preferably comprises two flanges or discs 72 b spaced apart with a preferably cupped washer of rubber, leather or other suitable material 0 therebetween. The washer 0 is preferably a loose fit around the piston whilst the under or inner face of the upper disc 6 is formed with an annular groove or channel. When air under pressure is admitted to the interior of the barrel ait acts upon the under face of the washer 0 and presses the same upwardly into contact with the edge of the upper disc 6 the area of which will be less than that of the washer o and simultaneously the outer periphery of the washer is pressed into contact with the barrel. Now since air is permitted to pass through the small annular space between the washer 0 and the central portion of the plunger 6 thus nearly balancing the pressure above and below the former, it will be seen that the latter can make a slight upward movement without a similar movement of the'washer thus relieving the latter of a certain proportion of the load. should it be tending to stick and thereby allowing the pressure to act with better effect 011 its excess of area, such construction, which may be modified, being with the object of securing a free movement rather than a. movement of upward jerks.

It will be understood that immediately the dust cap 72, is placed in position, the rod 0 will be depressed causing the passage a to be closed by the valve 2'.

The lower groove 0 coincides with the upper edge of therecording cap when the pressure of air within the tyre has exceeded the pressure at which the loading plug has been set, so that in all cases at whatever pressure the loading plug has been set, the movement of the tubular rod 0 and the plunger is limited. If desired the rings 0 and 0 may be coloured red, so as to better show when the pressure reaches the predetermined degree.

It will be understood that the details of construction and the arrangement of parts may be modified without departing from said piston, co-op'erating with a port load-t rod to cut oif communication between said casing and the interior of the tyre.

4-. A combined valve and pressure gauge adapted for use with pneumatic tyres and the like, comprising in combination a casing, a slidable piston on said casing, a loading plug adjustably connected to said casing, a spring between said loading plug and said piston, serving to enable the load on the spring to be set to enable the piston to func tion at any predetermined pressure, a record ing cap attached to said casing and rod connected to said piston extending through said loading plug and cap and having grooves thereon co-operating with the upper edge of the recording cap when moved by the air pressure within the tyre to an invariable eX- tent, and serving as a feele'r and sight gauge to indicate when the pressure within the tyre has reached or exceeded the pressure for which the loading plug has been set.

5. A combined valve and pressure gauge adapted for use with pneumatic tyres, comprising in combinatl'on, a casing, a slidable piston in said casing, a loading plug having a screw threaded engagement with said casmg, a recording cap having a screw threacL ed engagement with the exterior of said easing, a spring between the upper face of said piston and said loading plug, a rod attached to said piston and extending through said ,40 co-operating with the upper edge of said loading plug and cap, markings on said rod cap, a longitudinal groove in said rod, a ring threaded on to said rod, a PIOJGCtlOIl on said ring, engaging said groove, a longitudinal groove on the interior of said casing and a pro ect1on on the periphery of the ring engaging the roove 1n the casing.

JOHN EL H-INSTONE GRAHAIVL 

